Stocking and method of sewing same



l atentecl Nov. 28,

steepness are?) Merl-ion er sun/rue seller.

William M. Carlin-Glen Ridge, N. 5., assignor to iihefiillarlrdhread ldompaiiy, Inc., a corporation of Delaware No lflrawing. Qriginal application April '12, 1946;- Scrial No. 661,912, new Patent No. 2,483,455; dated Geteber 4, 1949. Divided and this ap plication January 24, 19i'l,Serial Noflmflgw This invention relates to sewing thread composed of continuous filament yarns of thermoplastic material, preferably nylon, with respect to which the invrmtion will be described in ,detail.

Among the major objeetsoi the invention are the provision of a Jsewing thread of improved abrasion resisting .quality and so treated as to give increased strength, resilienc and flexibility to seams sewn with the thread. While by no means llimited thereto, athread made in accordance with :one "form of the invention has been found :to beef particular value in the sewing of stockingseams, it having been demonstratedthat, lengthwise, such seams may have a breaking strengthasrbigh as twenty-five pounds as compared with a breaking strength of only ten pounds for similar seams sewn with ordinary nylon thread as heretofore used for the purpose.

{Ihe invention ,is applicable to threads :incorporating any desired number of cords or usually 2, 3 or l, and of any given denier, the continuous. filaments composing the yarns being of thermoplastic material and, as stated, preferably nylon.

in the manufacture of the thread, the multiple filament yarnsare first twisted individually and then given an opposite finishing twist. It ,has been-found "that in order to achieve the desired results the yarn twist applied should be relatively high. .While not deemed high for cotton yarns, for example, the twists indicated ,in presenttinstance -willrbevrecognized as being relatively high for nylon and like synthetic yarns. Specifically, the number of turns of yarn twist applied is represented by the formula wherein D represents the denier of the yarn. For example, in the case of ll) denier threads commonly used in the sewing of hosiery, the applied yarntwist is about 40 turns, say, right.

Next, the yarns are assembled with a finishing twist appropriate to produce a balanced twist thread and, again, the twist is relativel high. This finishing twist incorporates approximately the number of turns given by the formula s .Clairns. (Cl. ea-239) 4.0 denier 3/cord thread the finishing twist aboutf22 turns, left. i

The following table is illustrative of :the applied twists determined by the aboveiormulaefor various thread sizes and numbers of cords -or yarns:

Denier Cord Yarn Twist Finishing Twist 30 2 46 tums right 31 turns left 30 3 46 turns right 25 turns left 40 2 iO -turns'right 27 turnslcft 40 3 40 turns right 22 turns lef t '2 30 turns right 19 turns-left 70 3 30 turns right 17 turns left 70 4 SOturus right 14 turns left 3 25 turns 1" it -14 turns left 105 4 25 turns right 12 turns left 1 210 3 1;? turns right 10 turns left 210 4 '17 turns right 8 turns left After the yarns have been so twisted and assembled, the thread is subjected towhat for con? venience is termed anaqueous boil, aswith soap and caustic, in orderto remove anysoil and to preshrink =;the vthread, ,and thereafter is further shrunk and set, preferably by steam and ,at,,a

temperature of about 245 F. Steam at 151125, According to this ,prer. ierred=method-the thread must be in a relaxed pressure {is appropriate.

condition throughout, skeins, for -ex'ample or loosely wound, in orderlto accommodate the shrinkage which results and which, it will lbe understood, increases the twist previously :ape'

plied and thereby increases .theiextensibility'of therthreacl.

in "the .nianufac'ture ref nylon stockings the v use of the thread manufactured as above described gives rise to :sundry advantages and imparts .'to

the finished. stocking certain/novel characteristics thread is, to all intents and purposes, quite unaffected by the preboarding process. In a nylon stocking so made, the resulting seam is found to be substantially as elastic or extensible, lengthwise of the stocking, as the body of the stocking and, consequently, the stresses to which the stocking is subjected in use are no longer concentrated in the seam. Undue strain of the seam is thereby avoided. A balanced structure results in which the strength of the seam is greatly enhanced, being no longer dependent, as was virtually the case heretofore, upon the strength of the seam thread alone. It has been found that, due to the elasticity of the described seam, the stocking as a whole is very much more elastic in the direction of its length, thereby adapting any given stocking to varying leg lengths without undue strain on the stocking or its means of support. Also, the stocking presents a better appearance when worn in that it fits better, especially around the ankles, where the normal seam thread is apt to pull and present a more or less wrinkled appearance; and its elasticity is conducive to maximum comfort for the wearer.

Where a thread of lower extensibility but of non-shrinking characteristics is required, as for the sewing of fabrics or material calling for heavy stitching, such as corsets, mens clothing, leather goods and so forth, the process is modified in certain particulars.

The yarns are separately twisted and given a finishing twist as above described. In the next step, however, the thread is treated to a partial setting step which substantially reduces subsequent shrinking. This step (corresponding in general to the final step of the first described method) involves subjecting the thread to steam pressure at about 245 F.; but, in this modified process, the thread is so wound or rigidly held as to restrain shrinkage. Thereafter, the thread is subjected to the aqueous boil in a relaxed condition, resulting in a slight shrinkage. It will be understood that during the autoclaving step, the thread need not be rigidly held to its full twisted length, although that is preferred. If the thread is autoclaved while held to something less than its full twisted length, the final thread will be of somewhat greater extensibility.

As indicative of the results achieved by the modification of the process, it has been found that if the thread, twisted as described, is first boiled in a relaxed condition, the shrinkage which results (in the case of nylon) is of the order of -11%; whereas, if the thread is first autoclaved while held substantially to its twisted length, the subsequent boil in a relaxed condition results only in shrinkage of the order of 2%.

Such a thread will not shrink if boiled only. If however, it .is subsequent1y autoclaved at fifteen pounds pressure, it will experience a shrinkage of about 4%.

Where threads of this lower extensibility but of non-shrinking characteristics are to be used for producing seams which are to be subsequently autoclaved, a final autoclaving of the thread in a relaxed condition should follow the aqueous boil.

This application is a division of co-pending application Serial Number 661,912, filed April 12, 1946, now Patent 2,483,455, dated October 4, 1949.

The following is claimed:

1. Inthe manufacture of seamed stockings of thermoplastic material, such as nylon, the method which includes the steps of sewing the stocking seam with preshrunk, pre-set, thermoplastic thread of the same material as the stocking, and subsequently subjecting the seamed stocking to a shrinking process at a temperature of about 245 F., said seam thread bein substantially nonshrinkable at said temperature.

2. In the manufacture of seamed stockings of thermoplastic material, such as nylon, the method which includes the step of sewing the stocking seam with a thermoplastic thread of the same material as the stocking and which has been given a yarn twist represented by the quantity and an opposite finishing twist represented by the quantity in which D is the denier of the yarns of the thread and Y the number of yarns per thread, said thread having been preshrunk by boiling in water and then further shrunk and set by contact with steam at about 245 F., and then subjecting the seamed stocking to a pre-boarding operation comprising treating it with steam at about 245 F.

3. In a seamed stocking of thermoplastic material such as nylon, the improvement comprising a seam made with a thread of the same thermoplastic material as the stocking, said thread having been given a yarn twist represented by the quantity and an opposite finishing twist represented by the quantity 7 in which D is the denier of the yarns of the REFERENCES CITED Ihe following references are of record in the file of this patent:

UNITED STATES PATENTS Numb-er Name Date 1,820,631 Penn Aug. 25, 1931 2,353,666 Hathorne et a1 July 18, 1944 2,396,166 Faucette Mar. 5, 1946 

